JP2023098452A - Heat sink structure and manufacturing method of heat sink used for the same - Google Patents

Abstract

To provide a heat sink structure having a corrugated heat sink plate made of a metal plate in which a plurality of crest parts and valley parts are formed, capable of obtaining an excellent cooling performance which can be easily manufactured.SOLUTION: A heat sink structure comprises a heat sink 2 in which a plurality of crest parts 3 and valley parts 4, extending in a fluid direction of a cooling fluid are alternately provided in a direction orthogonal to the fluid direction. In each inner side of the crest parts 3 and each inner side of the valley parts 4, each of flow channels 30 and 40 extending toward a downstream side from an upstream side in the fluid direction is formed. In the inner side of each crest part 3, a fluid speed increase part that increases a fluid speed for cooling fluid is provided in at least a middle part of the fluid channel 30 by reducing a cross section area of a downstream fluid channel compared to that of an upstream fluid channel.SELECTED DRAWING: Figure 1

Description

The present invention relates to a forced flow type heat sink structure with a corrugated heat sink and a method for manufacturing the heat sink.

Conventionally, in a corrugated heat sink arranged in a flow path of a cooling fluid to be forcibly flowed, a louver made of cut-and-raised pieces is provided on an intermediate wall portion between peaks and troughs so that the flowing cooling fluid (cooling A heat sink for a power module has been proposed in which a medium is swirled along a louver to make the temperature distribution uniform (see Patent Document 1).

However, depending on the flow rate of the cooling fluid, the flow is obstructed by the louvers formed of the cut-and-raised pieces, and heat is likely to be trapped inside the ridges, which may rather deteriorate the cooling performance. Moreover, there is also the problem that the processing for forming the louver is difficult and the manufacturing cost increases.

JP-A-2007-5673

Therefore, in view of the above-mentioned circumstances, the present invention aims to solve the problem by providing a forced flow type heat sink structure having a corrugated heat sink, which is easy to manufacture, can reduce costs, and provides excellent cooling performance. It is to provide a heat sink structure that can be

The present invention includes the following inventions.
(1) A corrugated metal plate having flow means for flowing a cooling fluid and a plurality of peaks and troughs extending in the flow direction of the cooling fluid alternately arranged in a direction orthogonal to the flow direction. a heat sink of a mold, wherein the heat sink has flow passages extending from the upstream side to the downstream side in the flow direction inside the ridges and inside the troughs, respectively; A heat sink structure, wherein a flow velocity increasing portion is provided in at least an intermediate portion of the flow path for increasing the flow velocity of the cooling fluid by narrowing the cross-sectional area of the flow path located on the downstream side to that on the upstream side.

(2) The cross-sectional area of the flow velocity increasing portion is narrowed by forming the left and right side walls of the mountain portion forming the flow passage closer to each other on the downstream side than on the upstream side. The heat sink structure according to (1).

(3) The shape is changed so that the left and right widths of the peaks of the mountain portions are narrower at the position on the downstream side than at the position on the upstream side. (2) The heat sink structure described.

(4) Lower ends of the left and right side walls of the peak portion are arranged closer to each other at the position on the downstream side than at the position on the upstream side. Heat sink construction as described.

(5) Flowing means for flowing cooling fluid, and a heat sink comprising a metal plate in which a plurality of peaks and valleys extending in the flow direction of the cooling fluid are alternately arranged in a direction orthogonal to the flow direction. wherein the heat sink has a first heat sink plate and a second heat sink plate made of a metal plate provided with the peaks and valleys, and the first heat sink plate and the second heat sink plate By vertically overlapping the peaks and valleys of the first heat sink plate and the corresponding peaks of the second heat sink, the upstream side in the flow direction and between each trough of the first heat sink plate and each corresponding trough of the second heat sink in the flow direction. Flow passages between valleys extending from the upstream side to the downstream side are respectively formed, and the first heat sink plate and the second heat sink plate are positioned at a position downstream from the position at the upstream side with respect to the depth of the vertically overlapping. are obliquely stacked along the flow direction so that the flow direction becomes deeper, so that the tops of the upper and lower peaks and the bottoms of the valleys gradually approach each other, and the flow passage between the peaks and the flow passage between the valleys are: A heat sink structure configured as a flow velocity increasing portion for increasing the flow velocity of the cooling fluid by narrowing the cross-sectional area located on the downstream side than on the upstream side.

In the heat sink structure according to the present invention, the cross-sectional area of the flow passage located on the downstream side is narrower than that on the upstream side at least in the middle of the flow passage on the inside of the crest where heat is likely to accumulate, and the cooling fluid is supplied to the cooling fluid. Therefore, when the cooling fluid flows through the flow path, the flow rate per unit time passing near the inner surface of the crest that contributes to heat absorption increases. That is, a large amount of the cooling fluid can be efficiently collected in the vicinity of the side wall to absorb heat, and the efficiency of heat dissipation can be improved. Moreover, such a flow velocity increasing portion can be realized by a simple process of only processing the shape of the ridges, and an increase in manufacturing cost can be suppressed.

Here, the cross-sectional area of the flow velocity increasing portion is narrowed by forming the left and right side walls of the mountain portion forming the flow passage closer to each other on the downstream side than on the upstream side. In such a case, such a form can be easily processed by pressing the left and right side walls of the peak, and can be easily realized while suppressing an increase in manufacturing costs. The fluid is pushed against the inner surface of the mountain portion by the flow velocity increasing portion so as to efficiently absorb heat from the inner surface, thereby increasing the efficiency of heat release.

In particular, the shape is changed so that the lateral width of the top of the mountain portion becomes narrower at the position on the downstream side than at the position on the upstream side. However, such a form can be easily realized by once forming peaks of the same cross-sectional shape over the entire length of the flow path, and then pressing the left and right side walls so that they are brought closer to the downstream side. An increase in cost can be avoided, and the flow velocity can be increased while the surface area of the crest inner wall remains the same along the flow direction, resulting in excellent cooling efficiency.

Further, the lower ends of the left and right side walls of the peak portion are arranged closer to each other at the position on the downstream side than at the position on the upstream side. Such a form can be obtained by once forming peaks and valleys of the same cross-sectional shape over the entire length of the flow path, and then deforming so that the neighboring peaks on the downstream side are brought closer to each other (as a result, the valleys are also closer to each other). It can be easily realized without press work or the like, and an increase in cost can be avoided. Further, in such a heat sink, not only the inner surface of the peak but also the inner surface of the valley have a smaller cross-sectional area toward the downstream side, and the inner surface of the valley also has a flow velocity increasing portion, so that the cooling efficiency can be further improved. In addition, such a heat sink can also increase the flow velocity while maintaining the same surface area of the inner walls of the peaks and the inner walls of the valleys along the direction of flow, resulting in excellent cooling efficiency.

The first heatsink plate and the second heatsink plate are made of a metal plate provided with peaks and valleys, and the peaks and valleys of the first heatsink plate and the second heatsink plate are separated from each other. By stacking the portions vertically, the heat sink extends from the upstream side to the downstream side in the flow direction between each peak portion of the first heat sink plate and each corresponding peak portion of the second heat sink plate. Flow passages between peaks are respectively formed, and between each valley of the first heat sink plate and each corresponding valley of the second heat sink, from the upstream side to the downstream side in the flow direction. and the first heat sink plate and the second heat sink plate are stacked in the flow direction such that the depth of the top and bottom stacks is deeper at the downstream side than at the upstream side. , so that the tops of the upper and lower peaks and the bottoms of the valleys gradually approach each other, and the flow passage between the peaks and the flow passage between the valleys are both located on the downstream side In a heat sink structure configured as a flow velocity increasing portion that increases the flow velocity of the cooling fluid by narrowing the cross-sectional area from that of the upstream side, the cooling fluid flows through the flow passages between the peaks and the flow passages between the valleys. In this case, the flow rate per unit time passing through the vicinity of each passage inner wall that contributes to heat absorption increases. Efficiency can be increased. Further, such a form can be easily realized by simply arranging the corrugated first heat sink plate and the second heat sink plate so as to overlap each other without pressing or deforming each heat sink plate. possible and avoid cost increases.

1 is a perspective view showing a heat sink structure according to a representative embodiment of the invention; FIG. FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1; CC line sectional view of FIG. BB line cross-sectional view of FIG. Explanatory drawing which similarly shows the manufacturing procedure of the heat sink used for heat sink structure. Explanatory drawing which similarly shows the modification of the shape of the peak part of a heat sink. Explanatory drawing which similarly shows the modification of the form of the flow-velocity increase part of a heat sink. FIG. 4 is an explanatory view showing another modification of the form of the flow velocity increasing portion of the heat sink. Explanatory drawing which similarly shows each other modification of the form of the flow-velocity increasing part of a heat sink. The perspective view which shows the modification of the heat sink structure of this invention. FIG. 10 is a cross-sectional view along the line AA of FIG. 10; CC line sectional view of FIG. Explanatory drawing which similarly shows a mode that the heat sink concerning a modification is deform|transformed. The perspective view which shows the other modification of the heat sink structure of this invention. FIG. 14 is a cross-sectional view along the line AA of FIG. 14; CC line sectional view of FIG. Explanatory drawing which similarly shows the procedure which manufactures the heat sink concerning a modification.

As shown in FIGS. 1 to 4, a heat sink structure s1 according to a representative embodiment of the present invention includes a flow means 1 for flowing a cooling fluid 9 and a plurality of ridges 3 extending in the flow direction of the cooling fluid 9. and a corrugated heat sink 2 made of metal plates, in which the troughs 4 are alternately arranged in a direction orthogonal to the flow direction. Flow passages 30 and 40 extending from the upstream side to the downstream side in the flow direction are formed inside the peaks 3 and inside the valleys 4, respectively. The peak portion 3 is a substantially inverted U-shaped portion when viewed in cross section, and the valley portion 4 is a substantially U-shaped portion when viewed in cross section. The valley portion 4 is defined by the left and right side walls 34 and the bottom wall 41 of the bottom portion (lower portion).

In particular, at least in the middle of the flow passage 30 inside the peak portion 3, a flow velocity increasing portion 6 is provided for increasing the flow velocity of the cooling fluid 9 by reducing the cross-sectional area of the flow passage 30 located on the downstream side compared to that on the upstream side. It is In this way, by providing the flow velocity increasing portion 6 in the flow passage 30 inside the mountain portion 3 where heat tends to be trapped, the cooling fluid 9 flows through the flow passage 30, and the inner surface of the mountain portion 3 contributes to heat absorption. The flow rate per unit time passing through the vicinity will increase. That is, a large amount of the cooling fluid 9 can be efficiently collected in the vicinity of the side wall 34 of the peak portion 3 to absorb heat from the side wall 34, thereby improving the efficiency of heat dissipation.

As shown in the cross-sectional views of FIGS. 1 and 2 and 3, the flow velocity increasing portion 6 is arranged such that the left and right side walls 34 of the mountain portion 3 forming the flow passage 30 are positioned more downstream than upstream. are arranged closer to each other, so that the cross-sectional area of the flow passage 30 is gradually narrowed. More specifically, as can be seen by comparing the cross-sectional views of FIGS. 2 and 3, the lateral width of the top portion (top wall 33) of the peak portion 3 is larger at the downstream position than at the upstream position. The shape is changed so as to become narrower, and as a result, the left and right side walls 34 are arranged closer to each other toward the downstream side. According to such a configuration, the flow velocity can be increased while the surface area (inner surface area) of the peak inner wall remains the same along the flow direction, and excellent cooling efficiency can be obtained.

More specifically, as the cross-sectional shape of the flow path 30 changes from a rectangular shape on the upstream side to a triangular shape on the downstream side, it is located on the left and right sides of the flow path 30 from the center point (center of gravity) O of the flow path 30. The spacing of the distances to the side walls 34, 34 also varies, with the downstream position shown in FIG. 3 being closer from the center point O to the side walls 34, 34 than the upstream position shown in FIG. Therefore, on the downstream side where the flow speed of the cooling fluid increases, more cooling fluid is efficiently collected in the vicinity of the side walls 34, 34 to absorb heat, thereby effectively improving the cooling performance. . As shown in FIG. 6, another preferable example is one in which the side wall 34 is curved inwardly to further reduce the cross-sectional area.

As shown in FIG. 5, such a heat sink 2 is formed by forming a corrugated plate 102 having peaks 103 and valleys 104 of the same cross-sectional shape over the entire length of the flow path, and then pressing the plate 102. Specifically, the left and right side walls 34 of the ridge 103 are press-worked so that they are greatly shifted toward the downstream side. It can be easily processed. For the plate 102, a corrugated heat sink plate described in Japanese Patent Application Laid-Open No. 2018-129484, which has already been proposed by the present applicant, can be used.

It should be noted that the flow velocity increasing portion 6 can be formed not only over the entire length of the flow passage 30, but also only partially. For example, FIG. 7 shows an example in which only the downstream half region is configured. In addition to increasing the flow velocity by gradually narrowing the cross-sectional area, it is also preferable to increase the flow velocity by decreasing the cross-sectional area stepwise at one or more locations as shown in FIGS. 8 and 9(a). is. Furthermore, as shown in FIGS. 9(b) and 9(c), the flow in the flow velocity increasing portion 6 is also reduced by providing a relaxing region R1 that expands the cross-sectional area on the downstream side of the flow velocity increasing portion 6. This is a preferable example in that it can be promoted. Although an example in which the cross-sectional area is gradually increased is shown here, a structure in which the cross-sectional area is increased stepwise is also preferable.

The heat sink 2 of the present embodiment has through grooves 31 extending in the flow direction of the cooling fluid, that is, in the length direction of the ridges 3, in the upper side of the ridges 3, as in the heat sink plate of the above publication. are provided, and a pair of upright pieces 32, 32 are provided upright from the opening edge of the through groove 31. As shown in FIG. The standing pieces 32, 32 can be formed easily and at low cost by pressing a metal plate.

Specifically, the standing piece 32 has two long through grooves in a region excluding one end (supply side of the cooling fluid), an intermediate portion, and the other end (discharge side of the cooling fluid) of the heat sink 2. 31 is formed along the upper side of the peak portion 3 so as to extend in its longitudinal direction (see FIG. 1). The length, number, and intervals of the through-grooves 31 can be determined as appropriate. For example, three or more through-grooves extending in the longitudinal direction of the peak 3 may be provided, or one through-groove may be provided. good. The through groove 31 and the standing pieces 32, 32 may be formed by skipping one or more of the peaks 3. A structure in which the through groove 31 and the standing pieces 32, 32 are omitted may be employed.

Depending on the flow rate of the supplied cooling fluid, such a through groove 31 allows the cooling fluid such as cold air located above to flow into the flow passage 30 whose internal pressure is reduced according to the Venturi effect. The effect of smooth inflow and the effect of discharging excess fluid that cannot pass through the flow path 30 while absorbing heat are expected.

The flow path (30) inside the ridges (3) of the heat sink (2) of the present invention excludes the space between the upright pieces 32, 32 outside the through groove 31. The cross-sectional area is also excluded from consideration. In this case, the inner surface area is reduced at the position where the through-groove 31 exists, but the standing piece rises accordingly, so if the standing piece is included, the surface area is considered to be constant in the flow direction. can be done.

Such a heat sink 2 is composed of a metal plate such as a copper plate or an aluminum plate having high thermal conductivity. The bottom wall 41 of the trough portion 4 is fixed to the base member 5 fixed to an object to be cooled (not shown) such as an LED or CPU by caulking or a fixing pin 51 while being in close contact with the base member 5 . The base member 5 is made of a material having high thermal conductivity such as a copper plate or an aluminum plate. The base member 5 may be omitted, and the bottom wall 41 of the valley portion 4 may be brought into direct contact with an object to be cooled (not shown).

The flow means 1 is arranged on the upstream side of the heat sink 2 (inlet side of the cooling-side fluid), and includes a blower fan for sending the cooling fluid 9 to the peaks 3 and the valleys 4, and a cooling fluid from the downstream side (outlet side). It is composed of a suction fan for sucking the liquid 9, and fluid flow paths on the inlet side and the outlet side provided as necessary.

10-13 show modifications of the heat sink structure according to the present invention. As can be seen by comparing FIGS. 11 and 12, the heat sink 2 of the heat sink structure s2 according to this modified example has lower end portions of the left and right side walls 34 of the peak portion 3 at the position on the downstream side rather than the position on the upstream side. 34a are arranged close to each other, so that the left and right side walls 34 are close to each other.

Such a heat sink 2, as shown in FIG. 13, is formed by once forming a corrugated plate 102 having peaks 103 and valleys 104 of the same cross-sectional shape over the entire length of the flow path as described above, and then This can be easily realized without press work or the like, simply by deforming so as to bring the adjacent peaks closer together (as a result, the valleys also come closer together).

In this heat sink 2, not only the inner surface of the peak portion 3 but also the flow passage 40 on the inner surface of the trough portion 4 have a smaller cross-sectional area toward the downstream side. can be enhanced. Furthermore, such a heat sink 2 can also increase the flow velocity while maintaining the same surface area of the inner walls of the peaks 3 and the inner walls of the valleys 4 along the direction of flow, thereby achieving excellent cooling efficiency. In this example as well, the through grooves 31 and the standing pieces 32 are provided in the middle of the flow path, and the effects of these are as described above.

14-17 show other variations of the heat sink structure according to the present invention. The heat sink 2 of the heat sink structure s3 according to this modified example includes a corrugated first heat sink plate 24 made of a metal plate provided with peaks 3A and valleys 4A, and similarly provided with peaks 3B and valleys 4B. A corrugated second heat sink plate 25 made of a metal plate formed by lamination is stacked vertically on top of each other at the peaks 3A and 3B and at the valleys 4A and 4B. Flow passages 70 between peaks extending from the upstream side to the downstream side in the flow direction are formed between 3A and the corresponding peaks 3B of the second heat sink plate 25, and the first Between each valley 4A of the heat sink plate 24 and each corresponding valley 4B of the second heat sink plate 25, inter-valley flow passages 80 extending from the upstream side to the downstream side in the flow direction are provided. It is formed.

In particular, the first heat sink plate 24 and the second heat sink plate 25, as can be seen by comparing FIGS. They are obliquely overlapped along the flow direction so that the depth at the position on the side becomes deeper. (Bottom walls 41, 41) gradually approach each other toward the downstream side, and the cross-sectional areas of both the inter-peak flow passage 70 and the inter-trough flow passage 80 located on the downstream side are narrower than those on the upstream side for cooling. It is configured as flow velocity increasing portions 6 and 6A for increasing the flow velocity of the fluid 9 for use.

In the heat sink structure s3 of this example, when the cooling fluid 9 flows through the flow passages 70 between peaks and the flow passages 80 between valleys, the flow rate per unit time passing through the vicinity of the inner walls of each passage that contributes to heat absorption is In other words, more cooling fluid can be efficiently collected near the inner wall of each passage to absorb heat, and the efficiency of heat dissipation can be improved.

In addition, as shown in FIG. 17, such a heat sink 2 can be obtained by simply arranging a corrugated first heat sink plate 24 and a second heat sink plate 25 one on top of the other by pressing the respective heat sink plates. It can be easily realized without bending or deforming, and an increase in cost can be avoided.

In this example, the lower first heat sink plate 24 is provided with a through groove 31 extending in the length direction of the peak portion 3A and upright pieces 32, 32 (FIG. 17) in the same manner as in the examples described above (FIG. 17). reference). On the other hand, the upper second heat sink plate 24 is not provided with the through groove 31 and the standing pieces 32 , 32 , and the upper side of the peak portion 3 is closed by the top wall 33 .

It is also possible to omit the through groove 31 and the upright pieces 32, 32 provided in the peak portion 3A of the first heat sink plate 24 positioned below. However, when the through groove 31 and the standing pieces 32, 32 are provided in the mountain portion 3A of the first heat sink plate 24, the cooling fluid flowing inside the mountain portion 3A of the first heat sink plate 24 is controlled by the Venturi effect. , the cooling fluid can smoothly flow into the flow passage 70 between the peaks on the upper side, and the cooling fluid can be discharged through the flow passage 70 without heat buildup.

In addition, if the bottom of the valley 4B of the second heat sink plate 25 is provided with an upright piece protruding downward and a through groove, the second heat sink plate 25 above through the through groove from the flow passage 80 between the valleys can be displaced. This is effective in that heat buildup can be more reliably prevented by discharging or flowing the cooling fluid into the flow passage inside the valley portion 4B.

Although the embodiments of the present invention have been described above, the present invention is by no means limited to these examples, and can of course be embodied in various forms without departing from the gist of the present invention. For example, in the above description, as shown in FIG. Of course, it is also possible to manufacture the heat sink 2 having the enlarged portion by press working or the like.

Next, a cooling performance test was conducted on Example 1, which is a sample of the heat sink structure according to the present invention, and Comparative Example 1, which is a sample in which the heat sink of Example 1 does not have the conventional flow velocity increasing portion. The results will be explained.

(sample)
Example 1 was assumed to have the heat sink shown in FIG. Comparative Example 1 was in the state before deformation processing shown on the upper side of FIG. In all cases, the length and number of peaks and valleys, the material of the plate, the thickness, etc. were common, and they were installed on the upper surface of the base member.

(Test method)
10-watt LEDs were attached to the lower surface of the base member as objects to be cooled. The bottom surface temperature and the top surface temperature were measured respectively.

(result)
After 1 minute, the lower surface temperature was 26.6°C and the upper surface temperature was 26.2°C in Comparative Example 1, and the lower surface temperature was 25.7°C and the upper surface temperature was 25.1°C in Example 1. After 20 minutes, Comparative Example 1 had a lower surface temperature of 37.4°C and an upper surface temperature of 33.2°C, and Example 1 had a lower surface temperature of 36.1°C and an upper surface temperature of 30.8°C. rice field.

As described above, in Example 1 according to the present invention, the lower surface temperature decreased by about 1.3° C. and the upper surface temperature decreased by about 2.4° C. as compared with Comparative Example 1 after 20 minutes. confirmed. This is because the cooling performance of Example 1 is about 3.47% (=1.3° C./37.4° C.×100%) in terms of lower surface temperature drop rate, which is higher than that of the comparative example. This means that the rate of temperature drop is about 7.22% (=2.4° C./33.2° C.×100%), which is an improvement over the comparative example.

REFERENCE SIGNS LIST 1 flow means 2 heat sink 2 first heat sink plate 3 peaks 3A, 3B peaks 4 valleys 4A, 4B valleys 5 base member 6, 6A flow velocity increasing portion 9 cooling fluid 24 first heat sink plate 25 second heat sink plate heat sink plate 30, 40 flow path 31 through groove 32 upright piece 33 top wall 34 side wall 34a lower end portion 40 flow path 41 bottom wall 51 fixing pin 70 flow path between peaks 80 flow path between valleys 102 heat sink plate 103 crest 104 valley Part R1 relaxation region s1 to s3 heat sink structure

Claims (8)

A corrugated heat sink consisting of a flow means for flowing a cooling fluid and a plurality of ridges and troughs extending in the flow direction of the cooling fluid and arranged alternately in a direction perpendicular to the flow direction of the metal plate. and
The heat sink
Flow passages extending from the upstream side to the downstream side in the flow direction are formed inside the peaks and inside the valleys, respectively;
A flow velocity increasing portion is provided in at least a middle portion of the flow path inside the peak portion for increasing the flow velocity of the cooling fluid by narrowing the cross-sectional area of the flow path located on the downstream side compared to that on the upstream side. heatsink structure. The cross-sectional area of the flow velocity increasing portion is narrowed by forming the left and right side walls of the mountain portion forming the flow passage closer to each other on the downstream side than on the upstream side. Item 2. The heat sink structure according to item 1. 2. A shape change is made so that the left and right widths of the peaks of the peaks are narrower at the position on the downstream side than at the position on the upstream side, whereby the left and right side walls are closer to each other. Heat sink construction as described. 3. The heat sink according to claim 2, wherein the lower ends of the left and right side walls of the mountain portion are arranged closer to each other at the position on the downstream side than at the position on the upstream side, so that the left and right side walls are closer to each other. structure. a flow means for flowing a cooling fluid; and a heat sink made of a metal plate in which a plurality of peaks and valleys extending in a flow direction of the cooling fluid are alternately arranged in a direction orthogonal to the flow direction. ,
The heat sink
Having a corrugated first heat sink plate and a second heat sink plate each made of a metal plate provided with the peaks and the valleys,
By vertically overlapping the ridges and troughs of the first heat sink plate and the second heat sink plate, the ridges of the first heat sink plate and the corresponding ridges of the second heat sink are obtained. between the troughs of the first heat sink plate and the second heat sink corresponding to each of the troughs of the first heat sink plate. An inter-valley flow passage extending from the upstream side toward the downstream side in the flow direction is formed between each valley, and
The first heat sink plate and the second heat sink plate are obliquely stacked along the flow direction so that the depth of the vertically stacked heat sink plate is deeper at the downstream side than at the upstream side, thereby The tops of the upper and lower peaks and the bottoms of the valleys gradually approach each other, and the cross-sectional areas of the flow passages between the peaks and the flow passages between the valleys located on the downstream side are narrower than those on the upstream side. A heat sink structure configured as a flow velocity increasing portion for increasing the flow velocity of a fluid. A method for manufacturing a heat sink used in the heat sink structure according to any one of claims 1 to 3,
After forming a corrugated plate having peaks and valleys of the same cross-sectional shape over the entire length of the flow path,
A method of manufacturing a heat sink, wherein the heat sink is formed by pressing the plate. A method for manufacturing a heat sink used in the heat sink structure according to claim 3,
After forming a corrugated plate having peaks and valleys of the same cross-sectional shape over the entire length of the flow path,
A method of manufacturing a heat sink, wherein the heat sink is formed by pressing the plate so that left and right side walls of the ridges are shifted toward the downstream side. A method for manufacturing a heat sink used in the heat sink structure according to claim 4,
After forming a corrugated plate having peaks and valleys of the same cross-sectional shape over the entire length of the flow path,
A method for manufacturing a heat sink, wherein the heat sink is formed by deforming the plate so that adjacent peaks and valleys are brought closer to each other toward the downstream side.

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